Electrically powered endoscopic probes are described in and commonly assigned U.S. patent applications Ser. Nos. 877,476, filed May 1, 1992 and 07/959,240, filed Oct. 9, 1992. The devices described in those applications overcome many disadvantages inherent in previously known endoscopic probes.
The control of bleeding during surgery accounts for a major portion of the time involved in an operation. In particular, bleeding that occurs when tissue is incised or severed can obscure the surgeon's vision, prolong the operation, and adversely affect the precision of cutting. Blood loss from surgical cutting may require blood infusion, thereby increasing the risk of harm to the patient.
Controlling flow of blood from incised tissue is readily accomplished in "open" surgical procedures. The surgeon gains access to the target tissue by cutting large incisions through the body wall and displacing the overlying tissue to expose the tissue requiring treatment. A large opening is typically required to provide visibility and room to manipulate hands and instruments. Vital structures are held away from the operative site and shielded from inadvertent contact. The surgeon can directly touch and manipulate the various tissues. Bleeding from incised tissue is controlled by blotting or evacuating the accumulating blood. This step of removing the blood permits visual observation of the vessels for clamping or tying of those vessels to inhibit further blood loss.
In performing endoscopic surgery, the surgeon forgoes direct manual access to the tissue being operated upon. Consequently, traditional means of physically controlling bleeding (i.e., clamping and typing) are unavailable. Other techniques must then be employed to control bleeding during the surgical procedure. One such technique, which was first employed in "open" surgical procedures, is to thermally heat the bleeding tissue. Such thermal heating reduces the tendency of severed tissue to bleed. This process, referred to as "hemostasis," may be accomplished using either of two different endoscopic techniques to deposit sufficient heat in the tissue as described in the above-identified patent applications.
In U.S. patent application Ser. No. 07/877,476 a thermally autoregulated endoscopic probe is described, in which radio frequency electrical currents are used to maintain the working surface of the instrument at an auto-regulated temperature. The probe tip of that device comprises a heating element having a skin depth responsive to the temperature of the heating element and that decreases as the temperature of the heating element falls below the autoregulated temperature.
In my copending and commonly assigned U.S. patent application Ser. No. 07/959,240, a compact bipolar endoscopic probe is described, in which a probe blade suitable for operation at low drive voltages is provided for simultaneously cutting and cauterizing tissue. The probe blade includes a strong and flexible electrically insulative covering that reduces the possibility of losing the blade tip should undue loads cause it to fracture.
A difficulty encountered with use of the above described devices, as well as all previously known endoscopic instruments, is the inability to view the tissue as it is being cut. Despite the hemostatic action of the endoscopic probes described in the above-identified patent applications, there may nevertheless occasionally be inadvertent bleeding from a transsected vessel, the exact location of which may be difficult to identify because of the presence of active bleeding or a hematoma. Alternatively, where irrigation is provided by apparatus inserted through another cannula, the surgeon may be required to manipulate the irrigation apparatus to the site of the incision, thus creating a cumbersome arrangement of separate devices for the surgeon to control, again resulting in added effort and lost time.
It would therefore be desirable to provide irrigation apparatus to cleanse and/or evacuate the surgical site of blood and/or smoke.
It would further be desirable to provide irrigation apparatus that can be located at the surgical site with a minimum of effort and distraction to the surgeon.